It does, The diagram is clear to me.
The misfire IS intermittent. And it was already doing it before I became aware of the car's drinking problem.
I don't have the CO% figure to hand, but I can tell you that at MOT in april this year it passed it's emmisions test really convincingly.
I have had the top off of the ecu, and although I couldn't say 100% it isn't a non standard one, I'm fairly sure it is. If that isn't too much of a contradiction.